Functional and thermorheological properties of rice flour gels for gluten-free pasta applications

Based on the European Commission directives on circular economy, this work explores the functional and thermorheological properties of rice flour from broken kernels, a by-product from the rice industry, in order to evaluate its possible use in food applications, back into the value chain. Chemical and hydration properties of two rice varieties (Guiana - Indica spp, Ariete - Japonica spp) were accessed, as well as the impact of the rice variety on the texture and viscoelasticity of rice flour gels (6-26%). Both rice varieties presented statistically different physicochemical properties (protein, lipid and amylose contents), and hydration properties that support the distinct texture and rheology behaviour of gels obtained. Rheology results suggested the formation of a gel-network structure with high frequency dependence, especially at lower rice concentrations. Texture results suggest that both rice varieties could be suited for development of gluten-free products that require pre-gelatinised starch, such as pasta. The effect of gelatinised rice flour (10-25%) and gelatinised flour/rice flour ratio (40:60, 50:50, 60:40) on the physical properties and cooking quality of pasta were assessed. Better overall cooking quality and texture properties were obtained for the formulation with 20% gelatinised rice flour and 50:50 rice gel:rice flour ratio.